Evaluation of various substances and trap component configurations to increase mosquito collections in Biogents Gravid Aedes traps.

Two independent studies were conducted in northeastern Florida to determine if Biogents Gravid Aedes Trap (GAT) mosquito collections could be enhanced with a variety of substances and structural configurations. The first study baited GATs with either: 1) an infusion of mixed Southern live oak leaf (Quercus virginiana) and slash pine needle (Pinus elliottii) litter, 2) Biogents Lure (BG Lure), 3) yeast-derived carbon dioxide), 4) yeast-derived carbon dioxide+ BG Lure, or 5) a combination of all three. Nine mosquito species were collected from traps in the first study with Psorophora ferox>Culex nigripalpus>Aedes aegypti>Cx. quinquefasciatus as the top four most abundantly collected species. No significant difference in mosquito abundance was observed among these species among treatments. However, when the overall number of mosquitoes for all nine species was pooled, GATs baited with the combination of yeast-derived carbon dioxide + BG Lure + leaf infusion numerically collected the greatest number of individuals compared with the other four treatments. The second study evaluated the separate and combined attractiveness of individual GAT structural components/configurations with and without Southern live oak leaf litter infusion and BG-Lure. Aedes albopictus, Ae. aegypti, Anopheles quadrimaculatus, and Cx. quinquefasciatus were collected from all these traps in the second study. Results generally revealed that the current commercially available GAT configuration consisting of a screened translucent top (with BG-Lure) fitted into the black reservoir baited with oak leaf infusion remained the most attractive combination for collecting northeastern Florida mosquitoes.

Potential of Outdoor Ultra-Low-Volume Aerosol and Thermal Fog to Suppress the Dengue Vector, Aedes aegypti, Inside Dwellings.

A field study investigated penetration of outdoor ground ultra-low-volume (ULV) aerosol and thermal fog adulticide applications into a dwelling to control the dengue vector Aedes aegypti (L). Four applications of Kontrol 4-4 (4.6% permethrin active ingredient [AI], 4.6% piperonyl butoxide) at the maximum label rate were made at 25-30 m in front of a house at Camp Blanding Joint Training Center, Starke, FL, during summer 2016. The ULV sprayer and thermal fogger nozzles were oriented horizontally, and vehicle travel speeds were 16 and 24 km/h, respectively. All doors and windows of the house were left open. Spray efficacy was assessed using caged female mosquitoes positioned 30 cm above ground, outside and inside of the house. Interior cages were placed in open areas and cryptic sites (i.e., in a closet or cardboard box). A spinner holding 2 rods sized 3 mm × 75 mm was deployed next to each cage (except cryptic sites) to sample droplets and to quantify AI deposition. Thirty minutes after application, cages were removed, slides collected, and mosquitoes transferred to clean cages in the laboratory where mortality was assessed at 24 h posttreatment. The ULV application to the south side of the house produced 100% mortality in outdoor and indoor cages and 24% mortality at cryptic sites. Similarly applied thermal fog resulted in 85% mortality outdoors, 34% indoors, and only 4% in cages at cryptic sites. Application of either method from the west resulted in 19-61% mortality outdoors and 0.5-6.5% indoors. Droplet volume median diameter (Dv0.5) on rods from the ULV application was significantly larger compared with the thermal fogger outdoors, but similar indoors. Outdoors and indoors, the AI deposition from ULV was significantly higher than from thermal fog. Our results show the potential for controlling dengue vectors inside houses with outdoor ground ULV applications in areas where doors and windows are left open for ventilation.

Comparison of Mosquito Abundance From Biogents Sentinel 2.0 Traps With and Without Rain Covers.

Biogents Sentinel (BGS) traps have rapidly become a standard for adult Aedes aegypti surveillance. Several investigators have found that trap collections can be damaged easily by heavy dew or rain entering the trap intake port. In addition, water entering the trap may temporarily stop the fan, thus reducing the collection potential of the trap. We evaluated the effectiveness of a rain cover designed to minimize damage to mosquito trap collections from BGS 2.0 traps in a residential backyard in Jacksonville, FL. Rain covers consisted of white fiberglass 51-cm2 sheets positioned 19, 29, and 39 cm above the air intake of the traps. One BGS trap did not have a rain cover and was used as a control standard for comparison. All traps were baited with the BG-Lure. Generally, traps with rain covers resulted in higher mosquito counts when compared with collections from uncovered traps. Overall mosquito abundance was greater from traps with the rain cover positioned at 29 cm, but this difference was not significantly different when compared with the other cover heights. Covers spaced 29 or 39 cm collected significantly more Culex quinquefasciatus compared with traps at 19 cm and no cover. Species diversity was greatest for BGS traps with the rain cover positioned at 29 cm followed by 39 cm, 19 cm, and no cover; however, differences in diversity among the traps, with or without covers, were not significant.

Comparison of Adult Mosquito Abundance From Biogents-2 Sentinel and Biogents Gravid Aedes Traps In Northeastern Florida.

We compared the efficacy of the Biogents Gravid Aedes Trap (BG-GAT) and Biogents-2 Sentinel (BG2S) trap to assess differences in adult mosquito collection rates between these 2 mosquito surveillance methods in northeastern Florida. Species diversity of trap collections was significantly greater for BG2S than for BG-GAT, with 14 mosquito species collected from the former trap and 4 species from the latter. Aedes aegypti and Culex quinquefasciatus were the 2 predominant species collected in both traps. Overall, BG2S traps collected significantly more mosquitoes (in some instances nearly 5 times) than the BG-GAT, regardless of species. There was no significant difference between the 2 traps with respect to gravid status when total species and number of mosquitoes collected were compared. However, at the species level, 8% of Ae. aegypti were gravid from the BG-GAT collections compared with 1% from the BG2S. The number of gravid Cx. quinquefasciatus was also considerably greater (59%) for the BG-GATs than for BG2S traps (2%), but these relationships were not statistically significant due to high variability in collections between traps.